Manufacture of vulcanized rubber and of materials for use therein



Patented Oct. 7, 1930 CECIL JOHN TURRELL CRONSI-IAW AND WILLIAM JOHNSON SMITH NAUNTON, BLACKLEY, MANCHESTER, ENGLAND, ASSIGNORS TO BRITISH DYESTUFFS CORPORA- TION LIMITED, OF BLACKLEY, MANCHESTER, ENGLAND MANUFACTURE or VULGANIZED RUBBER sun or MATERIALS roa usn THEREIN No Drawing. Application filed August 15, 1927, Serial No'213,2-18,andinGreat Britain september 3, 1926.

this property to a degree worth while but the co-condensation product does.

Ne have found by experiment that neither the condensation product from acetaldehyde and a-naphthylamine, nor that from acetaldehyde and ,B-naphthylamine has any substantial accelerating influence in the vulcanization of rubber, and neither has any great etiect on the decrease of tensile strength of rubber vulcanized with their use when it is heated in a current of dry air. Thus, a mix consisting of Parts by weight Smoked sheet 45 Floating reclaim Mineral rubber 3 Zinc oxide 10 Gas black 10 Sulphur 2 Diphenylguanidine 0.3

was cured for minutes at 141 (1, and was found to have a tensile strength of 145 kilos. per square centimetre, which fell to 30 kilos. per sq. cm. aft-er treating for three weeks at 70-75 C. in a current of dry air.

Two mixes of the same ingredients in the same proportions as the foregoing were made and tested, one having an addition of 1.2 parts of the condensation product of acetaldehyde with alpha-naphthyl-amine and the other an addition of 1.2 parts of the condensation product of acetaldehyde with betanaphthylamine. Both showed a decrease in tensile strength on ageing as aboveone to kilos. to 50. x 7

.But we product fro-ma mixture of equal proportions of ocand ,G-nap'hthylamines with. acetaldeper square centimeter and the other hyde can be prepared, and this new body has i a most surprising effect on the ageing property of rubber vulcanized with a little of this newbody added. identical conditions with those described in the above three cases, but usingthe new condensation product, gave a: vulcanized rubber have found, that a condensation i Thus an experiment under whichhad on curing a tensilestrength of 140 Example. l.*Production of the new conand fl-napthylamines.

densation product from'acetaldehyde and oc- Afinelysgroundf -ixture be 72.5 parts of a-naphthylamine and 72.5 parts of fi-naphthylamine is suspended in l5 00 parts of 8.65

per cent'hydrochloricacid and stirred vioorously .in a closed vessel titted with a reflux condenser. 66 p then added and the mixture is stirred for about half an hour, being cooled as required.

The reaction mixture is now partially neutralized by addition of ,abo ut.,l350 parts of a per cent caustic soda solution. The precipitated product is filtered off, washed and dried.

This product is a brown powder, soluble in methylated spirits and partly soluble in toluene. It is completely soluble in a mixture of toluene and alcohol and is also soluble in dilute sulphuric acid and in hot stearic acid. It decolorizes a warm solution of potassium permanganate.

Example [I.Production of vulcanized parts of acetaldehyde are.

7-H H W llllll rubber of good ageing properties by the use of the product of Example I.

To a mix consisting of 45 parts of smoked sheet, 30 parts of floating reclaim, 3

parts of mineral rubber, parts of zinc oxide, 10 parts of gas black and 2 parts of sulphur, with 0.3 parts of diphenylguanidine as accelerator, are added 1.2 parts of the product prepared as in Example I. The

10 whole is cured for 45 minutes at 141 C. in

the usual manner.

What we claim and desire to secure by Letters Patent is:

1. .In theproduction of, age-resistant rubher, the step which comprises condensing with acetaldehyde a mixture of equal parts of aIpha-naphthylamine and beta-naphthyL amine in the presence of acid as a condensing agent, removing the acid and isolating the m iproduct, the said product being a brown powder, soluble in methylatedspirits, partly soluble in toluene, completely soluble in a mixture of toluene and-alcohol, soluble in dilute sulphuric .acid and in hot stearic acid,

w nmd decolorizing a warm solution of potas sium permanganate;

2; In theproduction of age-resistant rubber, the process which comprises condensing with acetaldehyde a mixture of equal parts wof'alpha-naphthylamine and beta-na hthylamine in the presence of acid as a con ensing agent, removing the acid, isolating the product; adding to a rubber mix in small proportions and vulcanizing the mix.

3. As a new composition useful in retarding the a eing of rubber, a condensation product 0 acetaldehyde with a mixture of alpha-naphthylamine and beta-naphthylamine in the presence of acid, the said con- 40 deneation product being a brown powder, soluble in methylated spirits, partly soluble in toluene, completely soluble in a mixture of toluene and alcohol, soluble in dilute sulphuric acid and in hot stearic acid and deoolorizing a warmsolution of potassium permanganate.

4; In age-resistant rubber, a rubber mix containing a condensation product of acetalehyde with a mixture of alpha-naphthylamine and beta-naphthylamine in the pres-v once of acid.

In testimony whereof we aifix our sig-' natures.

ECIL JOHN TURRELL CRONSHAW.

WILLIAM JOHNSON SMITH NAUNTON. 

